Radiophone amplifier



Dec. 9, 1924- 1 3,144.

A. N. MARTIN v RADIOPHONE AMPLIFIER Filed April 21 1923 INVENTOR V manyother distinctly disturbing and distor- Patented Dec. 9, 1924..

UNITED STATES Annual) n. .ZMARTIN, on NEW 1203?, NEW you.

BADIOPHONE AMPLIFIER.

Application filed April 21, 1923. Serial No. 633,649.

To all whom itmay concern:

Be it known that I, ALFRED N. MARTIN, a citizen of the United States,residing at New Dorp, Staten Island, in the county of Richmondand Stateof NewiYork, have in vented certain new and useful-Improvements inRadiophone Amplifiers, of which the following is a specification.

This invention relates tosound conduct ing and amplifying means of thereceiving type pertinent to radio operations,

Havmg 1n mind numerous objections to v a p y g 'q p t deVlceS 110W Fig.4 is a detail view of one of my imcommonly in use, suchas tinny, nasal,and

tive kinds of sounds, not traceable or chargeable to the originalbroadcasting of musical or-other sounds, in the development of thispresent equipment I contemplate a number of objectsamong which are themagnification or amplification of the transmitted sounds, whereby, Iobtain not --0I1ly unusual volume but particularly pleasing elfects,free or practically free from annoying or undeing apparatus peculiarlyconstructed for the '.purpose of producing sweet or favorable sirabletonal eifects; to provide an amplifytonequalities and which moreover aresubject to very delicate'or precise adjustment for thepurpose desired;to provide a system or apparatus for amplification of soundsat thereceiving station which includes means for magnifying the tones-in a.variable adjustable manner that is equivalent in this amplifyingconstruction to a rheostatand socket for tuning a vacum bulbin the nowcommonly used receiving set, that is, it not alone magnifies the sound,but by the balance or adjustment of the sound magnifier or microphone,it can be made to do duty in modifying and increasing the volume orintensity in the amplifying system in a peculiarly novel manner, andalso another object of my-invention is to obtain by a new and peculiarcombination of parts,"a result heretofore unknown, with respectespecially to the volume and quality of the tonal effect.

With the foregoing and other, objects in view the invention consists inthe arrangement and combination of'parts hereinafter described andclaimed, and while my invention is not restricted to the exact detailsof construction disclosed or suggested herein, still for the purpose ofillustrating a practical embodiment thereof reference is had totheaccompanying drawings, inwhich like proved microphones or tonemagnifiers.

Referring now more specifically to the drawings, but at the same timespecifically asserting my intention not to be unnecessarily limited tothe specific mechanism illustrated, I show a resonant body '10 which maybe thought of as being somewhat similar in size and construction tothe'body of a violincello but without a finger board or neck or otherexternal attachments except possibly a handle 11 which may be employedin moving and manipulating the apparatus. This body 10 includes a topcover 12 connected removably by any suitable means to. the rim portion13 and having also a bottom plate 14:.

The other main portion of-the supporting or casing construction is ahollow base or.

sub-support 15, the same being indicated as of generally rectangularform and-of rather shallow depth in proportion to its other dimensions.For convenience this base may be supported upon feet or legs 16- and 17,the latter being the shorter. The sub-support 15 except as now to bedescribed is entirely closed and in itself constitutes a soundamplifying medium. The top portion or cover plate 18 is provided with acentral opening 19 suitably shaped to receive therein the downwardlyconvexed central portion of the bottom of the body 10 which is clearlyshown in Fig. 2. The len th and breadth of the sub-support 15 may e lessor greater than the corresponding parts of the body 10, and these twomain parts are in practice secured or anchored together by any suitablemeans, as for instance, the hooks 20 shown in Fig. 2. At any desiredportions of the sub-support may be arranged sound vibration outlets eachshown provided with a belllike sounder or extremity. For this purpose Ishow three of such members connected at and extending thence laterallysideways or I I and 23both of which are preferably of the nature of thecommonly used B batteries for receiving sets. Within the body 10 I placea number of sound magnifiers or microphones of suitable construction andshown as four-in number at 24, one adjacent to each end of thebody andtwo others intermediate thereof, but all shown arranged in series or, ifdesired, parallel, and in the circuit with thetwo batteries justdescribed. Whether the coupling be in series or parallel will dependupon the nature or make up of the receiving set. Also arranged in thesame circuit are two loud speaking phones 25, one adjacent to each ofthe end microphones. The type of microphone best suited for this purpose is as shown in Fig. 4, the same comprising a carbon base plate 26and a tiltable or pivoted carbon stick 27 The stick is shown pivoted at28 within a fork 29 of an insulated bracket 30 close adjacent to oneside of the base plate 26. All the plates 26 are fixedg igidly to thebottom 14 of the body 19: One end of the-stick'27 is provided'with aseries of fingers or teeth 31 having relav tively sharp points, and thestick is so 'designed that these points will rest with more or less heftupon the plates 26. The firmness of this contact between the stick andthe plate is adapted to be varied or modified delicately or adjustablyby means of a rider or weight 32v movable along the upper end ofthe-stick and adapted to be fixed in adjusted position by means of a setscrew 33 or its equ valent. One connection of the circuit wire is madewith the base plate 26 and the other with the stick, the latterconnection being preferably through the pivot. It is the adjustablebalance microphone feature of this invention that is relied upon, inconnection with the B battery connections andloud speaking. phones 25,to produce the exceedingly well tuned-and well purified character tones,suitable for filling any reasonable room or auditorium, according tothe. control at the adjustable receiving set. Of course-thereis'nonecessity nor intention of employing head phones.

Located also preferably within the body '10 and-in close relation to thetwo intermediate microphones I provide' a number of other phones-34,preferably of the nature of loud speakin phones but which are coupled,indepen ently of the battery and head pieces.

wiring above described, to the receiving set in a manner similar to theusual coupling of The sounds received by and transmitted through thephones 5 and 34 pass through and are delivered from the sounding bodies10 and 15 with a remarkable sweetness and purity of quality as Wellasdepth of volume.

Variations may be resorted to within the spirit and scope of myinvention and parts thereof used without others.

The microphone circuit is operated through the vibration of theadjustable microphones by the sounding body wherein they are contained,the vibrations of the sounding body being transmitted to the microphones1 through the ,carbon base 26 attached to said body. These vibrationscause the resistance at 31 to vary so as to render the current flowingthrough the phones 25 a pulsating one, in unison with signals receivedthrough the primal set, causing them to operate so as to add to thetotal volume of sound to be amplified with- .in the sounding bodies 12and 15.

I claim:

1. In a sound amplifying means, a body of violin form, a hollow resonantsub-support for said body which lies in direct contact therewith, aportion of the wall of one of which within the line of contact has beenremoved to allow the adjacentcontacting wall to form a single partitionand common sounding board within said line, allowing the more readytransmission of sound therethrough for the purpose of amplification, andmeans to initiate sound vibrations to be amplified thereby.

2. Mechanism as set forth in claim -1 in which the resonant body ishollow and is provided with a convex bottom, and the sub-support isprovided with an opening into which said convex bottom is fitted.

3. Mechanism'as set forth in claim 1 in which the sub-support isprovided with a plurality of lateral openings.

4. In a sound amplifier as set forth, the combination of a hollowresonant body, a hollow resonant sub-supporting body therefor and towhich the first mentloned body is secured in fixed position, a pluralityof phones within one of the bodies operative from a radio receiving setto cause the vibration of the bodies, and microphone means within thebody in an independent circuit for the purpose of amp ifying the soundemanating from the phones, said microphone means being operative bymeans of vibrations transmitted to the same at their points ofattachment to the body.

5. The combination as set forth in claim 1 wherein the said means forinitiating sound vibrations comprises a plurality of phones within oneof the bodies operative from a receiving set to cause the vibrationofthe bodies, and microphone'meanswithin carbon base plate attached tosaid body, and 10 the same body in an independent circuit for a pivotedcarbon stick one end of which the purpose of'amplifying the soundemamakes contact with the carbon base plate,

nating from the phones, said microphone the electrical resistance ofsaid contact vai- 5 means being operative by means of vibra- 7 ing withthe vibrations transmitted to t e .tions transmitted to the sweat theirpoints microphone by the body. 15 of" attachment to the body. VIntestimony whereof I aflix my signature.

' 6. The combination asin claim 4 wherein the adjustable microphoneconsists of a r ALFRED N.'MA.RTIN.

